I have a sour mash that is going on 48 hours, and I'm hoping to press it closer to 72 as I like my sours bitter enough to strip the enamel off my teeth. Problem is by 24 hours (last night), I went to go check on the temperature, and it was very clear that heterofermentative lacto had settled in. The moment the lid came off, I had a walloping butter smell that required every window be opened to air it out. It was the most intense smell of diacetyl I think I'll ever encounter.
I heated the mash up to 140-150, ensuring that I kill off any bad (and good for that matter) bacteria, pitched dregs from a few sours (was too late to go pick up a vial at the homebrew store, had to swing by the liquor store instead). I let the mash cool down to 120, pitched in the dregs, and maintained temp again. The smell is still present, although not nearly as intense, and it certainly isn't getting any worse since killing it off.
My question is, once I go to ferment this wort, I'll pitch a dry English Ale yeast (WLP007). Will this (or any) yeast clean up whatever diacetyl remains in the mash as well as the diacetyl generated by the yeast during fermentation? I assume boiling won't kill off the flavor?
Update: It has been nearly two weeks and I am still getting very obvious buttery diacetyl characters in both the the aroma and the flavor. At this point it is difficult to tell whether the diacetyl has decreased during aging, but if I had to guess, I would suspect that it hasn't by any noticeable degree. It is a very low gravity beer, sitting at 3% ABV, so these sorts of off flavors really stand out. I was given the the suggestion elsewhere to get a yeast starter going and to pitch it at high krausen. While I dont see the harm in trying (other than wasting time and effort) is it worth the attempt when the diacetyl is still so prevalent? Am I too impatient at two weeks despite the low gravity?